How do you call a gesture of spreading one's hands and turning them palms up to suggest a question?
As in "what did you just do, man? That was so weird that left me speechless, so I had to raise my hands to show you I'm asking you stuff" or "Huh?"

Questions on English Language & Usage Stack Exchange are expected to relate to English language and usage within the scope defined by the community. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about reopening questions here.
If this question can be reworded to fit the rules in the help center, please edit the question.

As with most complex situations, there is no single word in English for the gesture that you are describing. Instead, a multiword description of what you mean, perhaps as you have just done, is how one talks about it.